Hook stick operated disconnect switch



Aug. 20, 1957 w. H. GILLILAND HOOK sncx OPERATED DISCONNECT swncu sSheet s-Sheet 1 Filed June 3, 1954 INVENTOR Wauu ll. fiuuua ATTORNEYS-Aug. 20, 1957 w. H. GILLILAND 2,803,726

HOOK STICK OPERATED DISCONNEICT SWITCH Filed June 3, 1 954 3Sheets-Sheet 2 INVENTOR W umn H Guuuwa BY W05 ATTORNEW 0, 1957 w. H.GILLILAND 2,803,726

HOOK sncx OPERATED msconuzcr swrrcu Filed June 3. 1954 3 Sheets-Sheet 3INVENTOR Waunn bf fiuluua ATTORNEK United States Patent 01 HOOK STICKOPERATED DISCONNECT SWITCH William H. Gilliland, Birmingham, Ala.,assignor to USCO Power Equipment Corporation, Birmingham, Ala., acorporation of Alabama Application June 3, 1954, Serial No. 434,257

14 Claims. (Cl. 200-162) This invention relates generally to electricalswitching apparatus and more particularly to hook stick operateddisconnect switches of the swingable blade type for engaging ordisengaging fixed or stationary contact members for respectively makingor breaking the electrical circuit.

It is an important object of this invention to provide a disconnectswitch having a pair of parallel, transversely spaced switch bladeshinged at one end with a contact member having transversely spacedcontact edges disposed between the blades and adjacent the hinge torelieve the hinge of the duty of carrying the current passing throughthe blades.

It is a further important object of this invention to provide adisconnect switch having a pair of transversely spaced, parallel switchblades with longitudinally spaced upturned contact members disposedbetween the blades adjacent opposite ends thereof and havingtransversely spaced contact edges in engagement with the blades when theswitch is closed.

It is another object of this invention to provide a disconnect switchhaving a pair of transversely spaced, parallel switch blades with anupturned contact member disposed between the blades adjacent the endthereof and having transversely spaced contact edges in engagement withthe blades when the switch is closed and with transversely disposedguide member to guide the blades as they descend to closed position onto the contact edges.

It is a further object of this invention to provide a disconnect switchhaving a pair of transversely spaced and parallel switch blades hingedat one end with upturned contact members disposed between the bladesadjacent opposite ends thereof and having transversely spaced contactedges in engagement with the blades when the switch is closed and with awedge-shaped curved arm pivoted on the blades adjacent the other end anda pair of upstanding complementary wedge-shaped arms having surfacescooperable with the curved arm to provide pry out means for opening theswitch.

A still further object of the present invention resides in providing ahook stick operated disconnect switch having a pair of transverselyspaced, parallel switch blades hinged at one end to an insulatorsupported hinge arm and longitudinally spaced, transversely extendinginsulator supported contact members disposed between the blades andproviding oppositely outwardly facing contact edges with a blade contactguide at the free end contact longitudinally offset with respect to saidcontact edges whereby the point of intersection between the blade andthe contact guide lies along an arcuate path removed from the normalline of contact between the blades and free end contact edges to therebyminimize frictional wear along the normal line of contact in the openingand closing of the switch.

Another object of the present invention resides in providing a hookstick operated disconnect switch having a pair of transversely spaced,parallel switch blades hinged at one end to an insulator supportedcontact clamp bracket for swinging movement to engage the other end witha spaced line contact with upturned line terminal contact elementsfastened to respective spaced insulators by the aforesaid contact clampbracket and a combined latch supporting, pry-out lug, clamp bracket withthe upturned contact elements positioned to span the space between theswitch blades inwardly between the clamp brackets.

A still further object of the present invention resides in providing ahook stick operated switch having a pair of transversely spaced, hinged,parallel switch blades and an insulator supported pivoted latchcooperating with a latch pin at the free ends of the blades with a latchreleasing and pry-out means in the form of a pivoted hook stickreceiving ring pivotally mounted on the latch pin and having a pair ofangularly related arms for respectively camming the latch to releasedposition and providing a leverage advantage for comming the switchblades out of closed switch position.

Still another object of this invention resides in the provision ofdisconnect switch having a pair of transversely spaced and parallelswitch blades hinged at one end to an insulator supported hinge arm,contact means disposed between said blades adjacent the opposite endsthereof for engaging the blades when the switch is closed, awedge-shaped curved arm pivoted between the free ends of the blades anda pair of upstanding complimentary wedge-shaped arms having surfacescooperable with the curved arm to provide pry out means for opening theswitch.

Another object of this invention is to provide a disconnect switchhaving a pair of transversely spaced and parallel switch blades hingedat one end and cooperating contact means disposed between said blades toengage the blades when the switch is closed with a wedge-shaped curvedarm pivoted between the free ends of the blades and providing anextension to be engaged by a hook stick and a pair of upstandingcomplementary wedge-shaped arms having surfaces cooperable with thecurved arm to provide pry out means for opening the switch whereby apry-out leverage advantage is obtained during the opening of the switch.

Further objects will appear as the description is read in connectionwith the appended claims and attached drawings wherein:

Figure l is a side elevational view of one embodiment of the presentinvention;

Figure 2 is an enlarged fragmental side elevational view of the free endcontact and pry-out structure of the embodiment of the invention ofFigure 1;

Figure 3 is an elevational view taken looking at Figure 2 from theright;

Figure 4 is an enlarged sectional view taken along line 4-4 of Figure 1looking in the direction of the arrows with certain parts broken awayand sectioned to better illustrate the blade guide and pry-out clampbracket;

Figure 5 is a top plan view of the hinge end contact clamp bracket ofFigure 1;

Figure 6 is a front elevational view of the hinge end contact clampbracket of Figure 5;

Figure 7 is a top plan view of the combined latch supporting, pry-outlug clamp bracket of Figure 1 provided for securing the free end contactelement in place on its supporting insulator;

Figure 8 is a side elevational view similar to Figure 1 illustrating amodified form of the invention provided for handling substantiallyhigher currents;

Figure 9 is a view on an enlarged scale taken on line 99 of Figure 8;

Figure 10 is an enlarged fragmental side elevational view, similar toFigure 2, of the embodiment of the invention shown in Figure 9; and

Figure 11 is a view similar to Figure 3 of the embodiment of theinvention shown in Figure 9.

With continued reference to the drawings wherein like reference numeralsare used throughout to indicate the same parts and with particularreference first to the embodiment of the invention shown in Figures 1through 7, numeral 20 indicates generally a hook stick switch of thepresent invention designed to handle currents of the order of 400 to 600amperes at a 7.5 through 69 kv. ratmg.

Switch 20 is mounted conventionally on insulator stacks 18 and 19 spacedapart on a supporting frame 17 in well known manner and comprises ingeneral a pair of parallel and transversely spaced blades 21 andterminal contacts 22 and 23 more fully hereinafter described. Blades 21are hinged on upstanding arms 24 of a clamp bracket 25. A hinge bolt 26mounted in arms 24 pivotally supports one end of blades 21 and isprovided with spring cup washers 27 bearing against the outer faces ofthe blades 21 and held between the head of the hinge bolt and a nut andlock nut assembly threaded on the end of bolt 26. This hinge bolt andwasher assembly constitutes a compression assembly which biases theblade ends toward each other to provide the desired high contactpressure in a manner that will be clear to those skilled in the switchart. As clearly seen in Figures and 6 bracket 25 comprises a baseportion 28, generally circular in configuration, having depending sideflanges 29 terminating at 30 and at 31 (Figure 5) to provide oppositelyaligned passages for receiving the base leg 32 of generally L-shapedcontact member 22 therebetween as shown in Figure 1. Base 28 of clampbracket 25 is provided with a bolt opening 34 lying on the center linebetween the terminal ends 30 and 31 of depending flanges 29 and a pairof bolt holes 35 transversely spaced in base 28 so as to lie outwardlybeyond the terminal ends 30 and 31 of depending flanges 29. Upstandingarms 24 of bracket 25, as clearly seen in Figures 5 and 6, are joinedthroughout their lower portions by a transversely extending web 36off-set outwardly from flattened end 37 of base 28 to provide a contactbacking web for a purpose to be hereinafter pointed out.

Web 36 as clearly seen in Figure 6 is provided with threaded aperture 38adapted in use to receive a contact securing bolt 39 (Figure 1) providedto clampingly secure upstanding contact element 41 of contact 22 againstbacking web 36 to rigidly secure the contact element 22 and clampbracket 25 together. As clearly seen in Figure 1, leg 32 of contactelement 22 extends longitudinally between the terminal ends 30 and 31 ofclamp bracket 25 and is suitably apertured in alignment with clampbracket bolt opening 34 to freely receive the shaft of a securing bolt43 threaded into the cap member 44 of conventional insulator stack 19.Cap 44 is also provided with a pair of transversely, outwardly disposedtapped bolt holes (not shown) in alignment with bolt holes 35 of clampbracket 22 to receive the shank of an attachment bolts 47 adapted tosecure clamp bracket 22 against relative movement with respect to cap 44and retain ends 30 and 31 of depending flange 29 hearing against theside faces of contact leg 32 to position contact element 22 properlyupon insulator cap 44. As clearly appears from Figmre l, the height ofdepending flange 29 is less than the thickness of leg 32 of contactelement 22 so that upon tightening of bolts 43 and 47 the contact leg 32will be rigidly clamped between cap 44 and clamp bracket 25.

In actual manufacture the spacing between switch blades 21 will be ofthe order of two inches and the side edges of the transversely extendingcontact 22 will be similarly dimensioned so as to overhang the sidefaces of upstanding arms 24 of bracket 25, which are respectively spacedapart one and seven-eighths inches to assure lateral protrusion of theupstanding contact element 41 beyond arms 24 in position to be closelyand tightly engaged by the switch blades 21 in use. As will be apparentfrom Figures 1 and 5, the upstanding arms 24 are longitudinally off-setwith respect to the exposed face of backing web 36 so that the contactelement 41 of contact 22 will lie inwardly of hinge pin 26 toward theadjacent contact supporting insulator stack 18. The side faces of arms24 adjacent their juncture with base 28 of clamp plate 25 are providedwith laterally protruding lugs 52, the top surfaces of which areflattened to provide open switch position blade stops as will now bepointed out.

Referring to Figure 1, it will be noted that the rear ends of the blades21 are cut away across one corner as indicated at 53. As a consequence,blades 21, when totated in a clockwise direction around hinge pin 26,will clear stops 52 until they reach a position approximately 90 removedfrom their closed position at which time the ends 54 of blades 21 willcontact the upper ends of stops 52 to limit the counterclockwisemovement of the blade at the full open switch position.

As will be clearly apparent from the dot-dash line showing of the blades21 in Figure 1, the width of the blades is such that full contact ismaintained between blades 21 and contact element 22 in all relativepositions of the blades between closed switch and open switch position.This being true and as the contact portion 41 of contact 22 at all timesengages the blades forwardly of the hinge pin and as the line terminalis directly connected to leg 32 of contact 22 through suitable boltholes 55 shown in Figure 1, it will be appreciated that the directelectrical path in all positions of the switch blades will be from theblades to the contact element 41 of contact element 22, through contact22 to the connected line terminal and that the hinge pin 26, springwashers 27 and clamp bracket 25 at no time provide the current pathbetween the switch blades and the line terminal at the hinge end of theblade. As a consequence, arcing due to pivotal clearances and endclearances between the blades and the support arms 24 is at all timesprevented and the heating up of the spring cup washers 27 that wouldlikely occur if the hinge pin carried the load current is avoided. Thespring washers, therefore, can be expected to retain their springresiliency indefinitely to assure adequate contact pressure between theblades 21 and contact element 41 over long periods of time withoutservicing.

It will also be appreciated that the solid backing of contact element 41provided by web 36 imparts substan tial rigidity to the upstandingcontact element 41 relieving the upstanding element of any stresses thatresult from opening and closing of the switch under the high contactpressure maintained by the hinge pin and washer assembly.

Insulator stack 18 at the forward end of the switch carries a cap 56which, like cap 44, is provided with three angularly spaced, tapped boltholes similar to those mentioned in connection with insulator cap 44 forreceiving similar securing bolts 43 and 47 provided to secure leg 57 ofcontact and terminal connector 23 between the base 59 of a combinedlatch supporting, pry-out lug, clamp bracket 61 and cap 56 in a mannersimilar to that heretofor described in connection with contact element22. As clearly seen from Figures 4 and 7, base 59 of clamp bracket 61 isgenerally circular in configuration and is provided with bolt holes 34and 35 and a depending flange 29 terminating at 30, 31 as previouslydescribed in connection with clamp bracket 25. Clamp bracket 61 also isprovided with a flattened side 37 corresponding to side 37 of bracket 25but differs in other respects as will be now pointed out.

Referring for the moment to Figures 1, 4 and 7, clamp bracket 61 at itsflattened side is provided with a centrally located upstanding backingweb or flange 62 flanked on either side by shorter upstanding lugs 63 ofrectangular cross section providing blade engaging stops for limitingclosing movement of the switch. The outer face of backing web 62 defineswith respect to the plane of base 59 an angle of 85 and is provided witha tapped opening 64 adapted to threadedly receive a bolt 65 which passesthrough a suitable opening (not shown) in upturned contact element 66 tosecurely fasten contact element 23 rigidly to bracket 61. Uptanding web62 has integrally formed therewith an upwardly and rearwardly extendingright angularly disposed rib element 67 the purpose of which will behereinafter pointed out.

Offset rearwardly beyond the transverse center line of clamp plate 61are a pair of laterally spaced, upstanding, integrally formed cars 68suitably apertured at 69 in transverse alignment to receive a pivot pin70. Pin 70, as clearly seen in Figures 1 and 2, pivotally mounts a latchelement 71 having a latch arm terminating in a latching finger 72carrying a right angularly disposed cam pin 73. Latch element 71 isspring urged to latching position by a coil spring in well known mannerand in angularly spaced relation around its hub is provided with a pairof opposite limit stop arms 74 and 75, the function of which will beapparent.

Leg 57 of contact element 23 like leg 32 of contact element 22 isprovided with spaced apertures 55 adapted to provide a connection for aline terminal in well known manner.

Referring for the moment to Figure 4 of the drawing, it will be notedthat the upper extremity of upturned contact element 66 tapers to apoint to provide inclined, upwardly facing guide surfaces 76 forcooperation with switch blades 21 in a manner to be hereinafter pointedout. Contact element 41, as indicated at 77 in Figure 1, has shortinwardly sloping walls terminating in a flat transversely extending topend wall 78. However, due to the constant contact engagement at thehinge end, the switch surfaces 77 normally have no guiding function.

As clearly seen in Figures 1, 2, 3 and 4 the ends of switch blades 21remote from hinge pin 24 are connected together by a compressionassembly made up of a headed bolt 81, the shank 82 of which extendsthrough suitable openings provided adjacent the free ends of blades 21,a pair of cup spring washers 83 supported on shank 82 in engagement withthe outer faces of switch blades 21 and a lock nut assembly 84. Thiscompression assembly is effective to bias the free ends of switch blades21 toward each other to create the desired high contact pressure in amanner well known in the art.

Shank 82 of bolt 81 also serves as a journal pin for mounting hook stickoperating ring member 85 pivotally journaled on shank 82 by means oftransversely spaced segernental end walls 86 integrally connected attheir outer ends by arcuate wall portion 87. Wall 87 supports intransverse centered relation ring element 88 into which the hooked endof a hook stick. is inserted to operate the switch. Each end of ringshaped element 88 at its juncture with arcuate wall 87 is provided witha reinforcing web 89 provide to strengthen the ring element againststresses concentrated at the juncture with angular wall 87 in operationof the switch.

End walls 86 at their opposite corners of intersection with annular wall87 are provided with transversely extending lugs 99 and 91 (Figures 1, 2and 3) adapted respectively to engage the free ends of switch blades 21in closed position and the longitudinal edges 92 of switch blades 21 inopen switch position of the blades. Hook stick ring member 85substantially midway between its end walls 86 is provided with apartition Wall (not shown) having an opening thercthrough to receiveshank 82 of pin 81 and supporting thereon a pair of angularly related,outwardly extending arms 94 and 95 (Figure 2). Arm 95 is formed with acurved cam surface 96 adapted to overlie rib 67 for cooperationtherewith to provide a pry-out mechanism for overcoming the highpressure contact forces incident to initial opening movement of theswitch. This cam surface 96 in actual production is generated around acenter disposed one and five-sixteenths inches to the right of thecenter of the journal opening provided for pin 82 and one inch below thecenter of the journal opening viewed in Figure 2.

Ring element 88 is formed around a center located two and five-sixteenthinches above the center of the journal opening and one and one-quarterinches to the right thereof using a one and one-half inch radius to formthe inner curved portion lying adjacent wall 87, the straight portionsproviding the hook stick corner notch 97 at their intersection beingright angularly related tangents to the resulting arcuate surfaces.These dimensions and center locations provide in actual practice apry-out ring assembly having a three to one leverage advantage with thetop of rib 67 as the fulcrum when a hook stick is engaged in cornernotch 97 to operate the hook stick operating ring assembly in theconventional manner. It follows, therefore, that, when ring element 88is engaged by a hook stick, arm 94 will first contact latch pin 73forcing the latch to its unlatched position and then cam surface 96 offinger will engage the top of rib 67 providing a force multiplication,due to the leverage advantage, to pry the switch blades away from thebracket 61 in a clockwise direction. This leverage advantage accordinglyis available to readily overcoming the initial resistance to movementdue to the high contact pressures and during the first portion of theopening movement of the switch until the area of contact between contactelement 66 and blades 21 is reduced sufficiently to permit the switch tobe fully opened with a minimum of effort.

Blades 21 just beyond the face of contact element 66 nearest the hingeend of the switch is provided with a further compression assemblyincluding a bolt 81, cup spring washers 83 and lock nut assembly 84 toassure the maintenance of proper contact pressure between blades 21 andcontact 66. To further assure unitary movement and assembly of blades21, the two blades are anchored together by a U-shaped copper bar 98having its opposite end flanges 99 riveted to the respective blades bymeans of rivets 101. As clearly seen in Figure l, anchoring bar 98 ispositioned approximately mid-way between the ends of the blades so thatthe opposite free ends of the blades may be flexed independently underinfluence of their respective compression assemblies. Also as clearlyshown in Figure l, the free ends of the blades 21 are cut off at anangle as indicated at 102 to permit free passage of stop 90 in aclockwise direction during opening movement of the switch.

The contact edges of contact elements 41 and 66 are silvered asindicated by the letter S over the area covered by blades 21 in closedswitch position to assure maximum contact efficiency. Due to theconstant contact of blades 21 and contact 41 the silver coating on thehinge end contact is subjected only to rubbing contact with the widefaces of blades 21 and will not be materially injured by the usualopening and closing switch movements. The silver coating on contactelement 66, however, would be subjected to highly injurious tearingforces, except for the backward sloping of contact element 66 whichdisposes the guide surfaces 76 in a position to engage the faces ofblades 21 beyond the contact area of the faces. Accordingly, the bladeedge in normal closing movement of the switch will make contact withguide surfaces 76 along an arcuate path G beyond the normal contact areaof the blades and will be spread apart during closing movement of theswitch by contact along this path with uncoated corners of contact 66.As a consequence wear and burring of the blades faces at points thatmight injure the silver coating or outwardly displace the blades isavoided in a simple and effective manner.

A modified embodiment of this invention is illustrated in Figures 8through 11 of the drawings. The switch there shown has a 7.5 through 69kv. rating but is adapted for use with currents ranging between 1200 to2000 amperes. Except for differences hereinafter pointed out theelements of this switch are the same as the previously describedembodiment and for this reason many of the parts are indicated byidentical reference numerals without detailed description.

The most important difference between the switch of the presentembodiment and that previously described is the provision of multiplecontact elements and provision of blade guide means formed as extensionsof backing web 62 of the clamp bracket 61. As clearly seen in Figure 8,the contact member at the hinge end of the switch is made up of contactelement 22 providing contact portion 41 and a similar contact member22a, leg 32a and contact portion 41a of which are slightly shorter thanleg 32 and contact portion 41, disposed in nested superposed positionwith their upturned contact portions 41 and 41a spaced one from theother. The desired spacing between contact portions 41 and 41a ismaintained by suitable spacer washers 111 disposed between the contactportions in surrounding relation to the four screws 65 provided tosecure the contact portions to backing web 36.

To accommodate the double thickness resulting from superposed legs 32and 32a, clamp plate 25 of this embodiment of the invention is providedwith a substantially deeper depending flange 29a but is otherwisestructurally the same as clamp plate 25 of the previous embodiment.

Turning to the contact structure on insulator 18, it will be noted thatit also is made up of a pair of contact members 23 and 23a, the legs ofthe latter being substantially shorter to permit nesting of contact 23ain contact 23 with legs 57 and 57a in superposed relation to each other.Contact member 23, as in the previous form of the invention providesupturned contact portion 66 terminating in a pointed upper end providinginclined guide surfaces 76. Contact 23a on the other hand has anupturned portion 66a terminating at about the level of the top of thebacking web 62.

As clearly seen in Figures and 11, backing web 62 is provided with twosets of laterally spaced attachment screws 65 having heads countersunkinto the face of contact portion 66 and shanks extending through spacerwashers 111 provided to space contact portions 66 and 66a apart andassure rigid clamping of the contact elements 66 and 66a to backing web62. It should be noted that the contact elements 66 and 66a of thisembodiment of the invention are disposed at a substantially 90 anglewith respect to their leg portions 57 and 57a and therefore, do notslope as does the contact 66 of the previous embodiment.

As a result of this difference in construction and to assure that thesilver contact coatings S will not be injured, backing web 62 of thepresent embodiment of the invention is made of double thickness alongits edges and extended upward beyond edges 92 of blades 21a where it iswidened out as indicated at 112 (Figure 9) to slightly overhang blades21a. The outer faces of these upward extensions are inclined inwardly toprovide guide surfaces 76a for guiding blades 21a into closed switchposition. As clearly seen from Figure 9, the main body portion of web 62is narrower than contact elements 66 and 660. As a consequence, blades21a, so long as any portion remains in contact with the corners 112,will be spread apart sufficiently to clear the silvered contact edges ofcontact portions 66 and 66a.

This embodiment of the invention omits pry-out rib 67 and in its placeprovides the upper portion of web 62 with an upwardly opening V-shapedrecess 113 the side faces of which are spaced apart sufiiciently toreceive a wedge shaped cam finger 114 formed as an extension of wall 87of hook stick operating ring assembly 85a. As will be apparent fromFigure 10, finger 114 is longitudinally reinforced by a rib 115 andassembly 85a is provided between its end walls with finger 94 forcooperation with latch pin 73 in the manner previously described.Instead of two spaced stops 90 and 91, end walls 86 of operating ringassembly 85a are each provided with a compound stop in the form of asingle, laterally protuding lug providing angularly related stopportions 90a and 91a.

In clogging movement of switch blades 210, stop 90a engages the freeends of blades 21:: to rigidly relate ring assembly a with the blades socounterclockwise movement can be effected with a conventional hookstick. In moving from closed to open position, ring assembly 85a firstpivots on the bolt of compression assembly 81 releasing latch 71. Duringthis initial movement, the tip of pry-out finger 114 moves freelythrough wedge shaped recess 113 until its side edges at the tip engagethe side walls of recess 113 at the small end. Continued pivotalmovement of ring assembly 85a produces a pryout force between the matingwedge surfaces of recess 113 and finger 114 initiating clockwisemovement of blades 21 toward open position. Since pivotal movement ofring assembly 85a is permitted until stop portion 91:: engages edges 92of blades 21a, it will be appreciated that approximately pivotalmovement of ring assembly 85a is provided in this form of the invention.During this pivotal movement finger 114 executes a form of rollingmotion in recess 113 progressively engaging successive areas of finger114 and recess 113 to maintain approximately a three to one leverageadvantage for a substantial period of time to overcome the frictionalresistance between blades 21 and contacts 41, 41a, 66, and 66a and bladeguide surfaces 112.

Referring to Figure 10, it will be noted that the silver stripping S isapplied to the contact edges of contact portions 66 and 66a in staggeredrelation. This assures against either of the contacts hogging" thecurrent in use of the switch.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. An electrical disconnect switch comprising a pair of insulator stacksrigidly supported in spaced relation to each other; a cap structureindividual to each insulator stack; a terminal connector disposed incontact with the top surface of each cap structure and providing anupstanding transversely disposed coated contact portion; meansassociated with each insulator cap and terminal connector for fasteningand immovably securing said terminal connectors to said insulator caps;a pair of switch blades hinged in transversely spaced relation to one ofsaid insulator caps for swinging movement around an axis longitudinaloffset outwardly beyond one of said upstanding contact portions andhaving a contact area adapted for constant engagement with the coatedupstanding contact portion and remote laterally moveable contact endsswingable toward and away from the upstanding contact portion on theother insulator stack to make and break a connection with said lastmentioned contact portion; guide means for spreading and guiding saidremote contact ends into laterally spaced relation to said contactportion of said other insulator cap to efiect non-sliding engagementtherewith, said guide means being offset longitudinally from said lastmentioned contact portion to obviate wear and burring of said remotecontact ends over the area engageable with said coated contact portionon the other insulator; and a hook stick operating ring pivotallymounted on said blades for moving said switch blades to open and closedswitch positions.

2. The switch of claim 1 wherein said contact portion of the terminalconnector associated with said other insulator stack is inclined awayfrom the hinged end of said switch blades and has its uppermost endformed by oppositely inwardly inclined surfaces providing said guidemeans and said guide means is aapte to engage the inner faces of saidlaterally spaced switch blades to guide said blades into contactingengagement with the lateral edges of said contact portion and spreadsaid blades apart by reason of engagement of the leading lateral contactedges of said contact portion along an arcuate path of said inner bladefaces other than the contact portion of said inner faces.

3. The switch of claim 1 wherein said means for fastening said terminalconnectors comprise respective clamp brackets and one of said clampbrackets is provided with upstanding, laterally spaced ears suporting ahinge pin for hingedly connecting said switch blades thereto.

4. The switch of claim 3 wherein said other clamp bracket is providedwith upstanding, laterally spaced ears supporting a pivot pin which inturn carries a latch means comprising a lever journalled on said pivotpin and having a hook shaped end for positive engagement with a portionof said switch blades, a stop arm for limiting movement of said lever inone direction, spring means formoving said lever in said one directionand a stop arm for limiting movement of said lever in the otherdirection.

5. The switch of claim 4 wherein said guide means comprises anupstanding formation on said other clamp bracket the upper end of whichis formed by oppositely, inwardly inclined surfaces the lower portionsof which extend laterally slightly beyond the lateral edges of the saidassociated contact portion to provide guide surfaces located adjacentbut spaced from one face of said contact portion to engage the innerfaces of said blades along an arcuate path spaced from the area of saidinner blade faces making electrical contact with the lateral edges ofsaid associated contact portion.

6. A disconnect switch comprising a pair of insulator stacks rigidlysupported in spaced relation to each other; a terminal connectorsupported by each of said stacks; an upstanding contact member supportedby each of said stacks electrically connected to the respective terminalconnectors and providing oppositely outwardly facing, laterally spacedcontact surfaces; a pair of switch blades hinged in transversely spacedrelation on one of said insulator stacks for swinging movement towardand away from the upstanding contact member on the other insulatingstack to make and break a connection therewith; an upstanding pry-outmember on said other insulator stack in adjacent relation to the contactmember thereon having a centrally located upwardly diverging recess inits upper end; and a hook stick operating ring assembly pivotallymounted adjacent the free ends of said switch blades and having a fingerportion of longitudinally curved Wedge shaped configuration disposed inoverlying relation to the diverging recess in said upstanding pry-outmember and adapted upon engagement of said hook stick operating ringwith a hook stick and pivotal movement of said hook stick operated ringin switch opening direction to enter into said recess and engage thelateral walls thereof with a rolling movement thereby effecting acontinuing pry-out action forcing said blades toward open switchposition and out of contact with said upstanding contact member on saidother insulating stack whereby the frictional pressure between saidblades and the contact surfaces of said last mentioned contact membermay be readily overcome with a minimum of effort until the area ofcontact is reduced to an inconsequential amount.

7. The disconnect switch of claim 6 wherein said contact and terminalconnector comprise a unitary bar having a short contact leg and a longterminal connector leg and said short contact leg and said long terminalconnector leg define between them a dihedral angle of the order of 85.

8. An electrical disconnect switch hinge end mounting comprising aninsulator stack; a cap on said insulator; a contact in the form of aflat copper bar seated on said (ill cap and having an upturned contactend; a clamp bracket removably secured against relative movement withrespect to said cap and having a recess therein for receiving saidcopper bar and clampingly engaging said copper bar to said cap; a pairof transversely spaced switch blades hinged to said bracket in positionto straddle said upturned contact end of said copper bar and engage thetransversely spaced edge portions of said upturned contact end.

9. A disconnect switch contact and terminal eonncctor structure for usein an insulator stack supported disconnect switch comprising an L-shapedcontact and terminal connector bar of substantial width having a shortleg containing a bolt opening and providing contact surfaces along itsupstanding edges and a long leg rovided with through openings adjacentits free end adapting said leg for connection to a line terminalconnector and a bolt opening adjacent said short leg; a clamp bracketcomprising a planar base having depending segmental flange portionsalong opposite sides thereof for receiving a portion of said longterminal connector leg therebetween. a plurality of bolt openingstherein one of which is located for alignment with the bolt opening ofsaid long leg of said L-shaped bar and the others of which are locatedin straddling relation to said long leg. and an upstanding planarportion narrower than said contact leg formed on the upper surface ofsaid base and extending laterally with respect to said segmental fiangeportions and located at an end of said base portion, said planar portionhaving a tapped opening in position to line up with the bolt opening insaid short contact leg when said contact leg is brought into contactwith its outwardly disposed face; fastening means having a threadedshank passing through the opening in said short contact leg and threadedinto said tapped opening in said planar portion to secure said contactleg rigidly thereto with its contact edges projecting laterally fromsaid planar portion; and fastening means for each of said bolt holes insaid base portion each of said fastening means having a threaded shankpassing through its respective bolt opening for threaded engagement withtapped openings in the top surface of said insulator stack to securelyfasten said clamp bracket to said insulator stack with said longterminal connector leg clamped between said clamp bracket base and thetop surface of said insulator stack.

10. The contact and terminal connector structure of claim 9 wherein saidshort contact leg and said long terminal connector leg define betweenthem a dihedral angle slightly less than and said outwardly disposedface of said upstanding planar portion is similarly inclined toabuttingly engage the inner face of said short contact leg.

11. An electrical disconnect switch comprising a pair of transverselyspaced switch blades; means spring biasing said blades toward each otherto assure a high contact pressure; a first insulator stack; means onsaid first insulator stack defining a hinge for said pair of blades; asecond insulator stack; a flat copper bar seated on said secondinsulator and having an upturned end disposed to be received betweensaid blades and provide transversely spaced oppositely facing contactedges for engagement with said blades; guide means on said secondinsulator defining an upwardly diverging recess between a pair oftransversely spaced, oppositely facing camming surfaces; a hook stickoperating ring disposed between and pivoted on said blades; and alongitudinally curved lever of wedge shaped cross-section on said ringhaving an end adapted to move into said recess and side faces to engagesaid camming surfaces to apply a substantially constant leverage pry-outforce during switch opening pivotal movement of said ring to overcomethe high contact pressure of said blades on said contact edges.

12. A switch comprising a pair of transversely spaced blades: a firstinsulator; means on said first insulator defining a hinge for said pairof blades; a second insulator; a flat copper bar seated on said secondinsulator and having an upturned end disposed between said blades andhaving transversely spaced edges thereon engaging said blades; a plateon said second insulator in clamping engagement with said copper bar; anoperating ring disposed between said blades and pivoted on said blades;an upstanding fulcrum member on said plate; and a curved finger on saidring having a free end adapted to seat on said upstanding fulcrum memberand form a prying means for said switch.

13. The switch of claim 12 wherein said curved finger lies between saidblades and provides a longitudinally extending arcuate cam abutmentsurface generated around a center disposed toward the hinge end of saidswitch and outwardly from said fulcrum member in the direction ofopening movement of said switch a distance just sufficient to assure aneffective leverage ratio of the order of 3 to 1 between the operatingring pivot center and the hook stick notch of the operating ring and theoperating ring center and the fulcrum point and said upstanding fulcrummember provides a planar end face extending lengthwise from saidupturned end of said bar toward said operating ring in the longitudinalplane of said curved finger in position to be rollingly engaged by saidarcuate cam abutment surface as the operating ring pivots during openingmovement of said blades thereby effectively progressively shifting thepoint of abutting contact between said finger and said planar end facetoward said upturned bar end as the pivot axis moves away from theplanar end face whereby the effective pryout force is maintainedsubstantially constant.

14. A high current disconnect switch having a pair of transverselyspaced and parallel switch blades mounted for pivotal movement into andout of engagement with a switch contact; and a high current switchcontact comprising a first upstanding member disposed between saidblades when the switch is closed and having transversely disposedcontact edges thereon engaging said blades, :1 second upstanding memberdisposed between said blades when the switch is closed and havingtransversely disposed contact edges thereon engaging said blades, a pairof transversely spaced upstanding arms, means securing said first andsaid second upstanding members to said upstanding arms, and a curved armpivoted on said blades and turnable to engage said upstanding arms todefine therewith pry-out means in the opening of said switch.

References Cited in the file of this patent UNITED STATES PATENTS1,819,779 Hoye Aug. 18, 1931 1,966,894 Jacobs July 17, 1934 1,971,392Carlisle Aug. 28, 1934 2,063,954 Ramsey Dec. 15, 1936 2,202,170 SmytheMay 28, 1940 2,498,250 Cole Feb. 21, 1950 2,531,165 Scheuermeyer Nov.21, 1950 2,566,917 Armstrong Sept. 4, 1951 2,630,510 Hoifman et al. Mar.3, 1953

